Convergence apparatus with convergence members on opposite surfaces of flat members



Feb. 21, 1967 5, ASHLEY ET AL. 3,305,807

CONVERGENCE APPARATUS WITH CONVERGENCE MEMBERS ON OPPOSITE SURFACES OFFLAT MEMBER 2 Sheets-Sheet 1 Filed July 2, 1965 INVENTORS: ROBERT B.ASHLEY, RAYMOND S. JOSEPH, JAMES V. VACCARO, BY

THEIR ATTORNEY.

3,305,807 BERS 2 Sheets-Sheet 2 TUS WITH CONVERGENCE MEM SURFACES OFFLAT MEMBER R. B. ASHLEY ET AL APPARA ON OPPOSITE CONVERGENCE Eli].

Feb. 21, 1967 Filed July 2, 1965 INVENTORS: ROBERT B. ASHLEY, RAYMOND S.JOSEPH JAM ES V. VACCARO, BY 7 5%? I THEIR ATTORNEY.

United States Patent CONVERGENCE APPARATUS WITH CONVER- GEN CE MEMBERS0N OPPOSITE SURFACES OF FLAT MEMBERS Robert E. Ashley, Raymond S.Joseph, and James Vaccaro, Syracuse, N.Y., assignors to General ElectricCompany, a corporation of New York Filed July 2, 1965, Ser. No. 469,161Claims. (Cl. 335-210) The present invention relates to apparatus forcontrolling the electron beams of cathode ray tubes and morespecifically to an apparatus for controlling the convergence of thevarious electron beams in a color cathode ray tube.

It is necessary in color cathode ray tubes of the multibeam type toeffect convergence of the various electron beams at the appropriatepoints of the aperture mask. In this regard magnetic core members havebeen commonly employed to achieve static convergence of the variousbeams, suitable windings also being positioned on the core members toprovide dynamic convergence.

More specifically, where in-line electron guns and thus linearly arrayedelectron beams are employed a pair of generally U shaped core memberscan be utilized to effect horizontal convergence, suitable means foradjustment being provided and coils being wound on the arms of each Ushaped core member to provide horizontal size correction. Similarly, apair of generally E shaped core members can be employed to achievevertical convergence, suitable means for adjustment again being providedand a coil being wound on the central arm of each E shaped core memberto achieve vertical size correction.

The prior art convergence assemblies in general have been both complexand expensive and in many instances did not afford the requisite ease ofadjustment. Further, the prior art assemblies have required specialfabrication techniques and have not been compatible with the use ofstandard mass production techniques. Indeed, no suit able convergenceassemblies whatsoever have been available for positioning the coremembers in the desired relationship to the various electron beams of anin-line gun tube.

Accordingly, an object of the invention is to provide an improvedconvergence assembly for use with a cathode ray tube employing multipleelectron beams.

Another object is to provide an improved convergence assembly whichemploys a minimum number of elements and which is less complex thanprior art devices.

Yet another object is to provide an improved convergence assembly whichis less expensive than prior art devices.

A further object is to provide an improved convergence assembly whichmay be fabricated through the use of standard mass productiontechniques.

Still another object is to provide an improved convergence assemblywhich is easily and exactly adjustable to achieve the requisiteconvergence.

Yet another object is to provide an improved convergence assemblysuitable for use with a color cathode ray tube employing plural linearlyarrayed electron beams.

These and other objects are achieved in one embodiment of the inventionthrough the use of a molded convergence assembly comprising a generallycylindrical support member adapted to receive the neck of the cathoderay tube, the generally cylindrical member including integral springportions which provide an interference fit between the generallycylindrical member and the tube neck. A generally fiat body member isformed integrally with the generally cylindrical member and extendsgenerally transverse with respect thereto.

A pair of E shaped magnetic core members are Patented Feb. 21, 1967mounted on one surface of the body portion, the E shaped magnetic coremembers being positioned on opposite sides of the generally cylindricalmember in diametrical opposition with each other. The body portion isprovided with a suitable receptacle for the E shaped core members andincludes integrally formed spring fingers for retaining the core membersin the desired position.

A pair of generally U shaped magnetic core members are slideably mountedon the opposite surface of the generally fiat body member in a positionsimilar to that of the E shaped core members. Each of the U shaped coremembers is mounted to an adjustable slide member, the slide member beingmolded and including integrally formed spring fingers for retaining theU shaped core in the desired position and for biasing the slide againstthe body member.

The novel and distinctive features of the invention are set forth in theappended claims. The invention itself together with further objects andadvantages thereof, may best be understood by reference to theaccompanying drawings in which:

FIGURE 1 is a partially exploded perspective view of the convergenceassembly of the invention,

FIGURE 2 is a front view of the convergence assembly shown in FIGURE 1,

FIGURE 3 is a back view of the assembly shown in FIGURE 1, and

FIGURE 4 is a top view of the assembly shown in FIGURE 1.

Referring to the partially exploded view of FIGURE 1, the convergneceapparatus of the invention comprises an integrally molded supportassembly including a generally cylindrical member 1 adapted to engagethe neck of a cathode ray tube and a generally flat body member 3extending transversely from the member 1. A pair of molded slideassemblies 5 are provided for slideably mounting suitable core membersto the support assembly. In accordance with an important feature of theinvention the support assembly and slide assemblies are easilyfabricated by injection molding of a suitable plastic material such aspolypropylene.

The generally cylindrical member 1 comprises first and second portions 7and 8 respectively, the portions 7 and 8 being joined by a pair ofintermediate integral spring loop portions 9. The generally cylindricalmember 1 further includes suitable apertures 11 for receiving the endsof the associated core members. A plurality of longitudinally extendingfingers 13 are provided as shown more clearly in FIGURE 4, a circularclamp being placed ove1r( these fingers to rigidly afiix the apparatusto the tube nec The generally flat body member 3 includes twoessentially identical portions extending from opposite sides of thecylindrical member 1 and formed integrally therewith. For purposes ofsimplicity, similar elements on each side of the generally cylindricalmember 1 are given identical reference numerals. Each portion of thegenerally fiat body member 3 is provided with a deck portion 14 having apair of side rails 15 formed integrally therewith and at right anglesthereto. Each side rail 15 is provided with a lip 17 to thereby define apair of tracks for slideably receiving the slide assembly 5. A pair ofintegral outwardly extending spring members 19 are provided on the deckportion 14, as shown more clearly in FIGURE 3, the spring members 19having a pair of apertures 21 associated therewith and serving tomaintain the associated core members in the desired position.

Each portion of the body member 3 is provided with a suitable terminalboard 23 having electrical terminals 25 associated therewith to whichmay be connected the leads of the various coils which are associatedwith the magnetic core members. In addition each deck portion 14 of thebody member 3 is provided with a screw receiving boss 27 having a hole28 therein for mounting the slide assembly in the desired position.

Identical slide assemblies 5 are positioned on opposite sides of thegenerally cylindrical member 1, the corresponding elements of each slideassembly being given identical numerals. For the purposes of clarity,one of the slide assemblies 5 is shown removed from the body member 3while the remaining slide assembly 5 is shown partially inserted in thetracks defined by side rails and the associated lips .17.

Each slide assembly 5 comprises a fl'at body member 29 having a pair ofrails 31 formed on the under surface thereof. The flat body member 29 isprovided with a plurality of outwardly extending integral spring fingers33 at the side edges thereof, the spring fingers 33 being adapted toengage the under surface of the lip 17 to spring bias the rails 31against the deck portion -14.

The slide assembly 5 is adapted to receive and retain a U shaped coremember generally shown at 35 by the provision of a plurality ofoutwardly extending positioning tabs 37 and a pair of integrally formedspring members 39 having apertures 40 associated therewith. An elongatedslot 41 is provided for receiving a suitable screw 43, the screw in turnbeing received by the hole 28 of boss 27. In this manner the slideassembly 5 is adjustable along the tracks defined by side rails 15 andthe associated lips 17 to an extent determined by the length of the slot41 in order to control the convergence of the various beams. A pair ofoutwardly extending finger tabs 45 are further provided to facilitateadjustment of the slide assembly 5 along the tracks.

The U shaped core member 35 comprises first and second L shaped portions47 and 49 respectively and a ferrite magnet 51 rotatably positionedtherebetween. The surfaces of core portions 47 and 49 abutting themagnet '51 are slotted at 52 and "53 respectively to rotatably receivethe magnet 51. The magnet 51 is polarized across its diameter so thatrotation of the magnet 51 between the core portions 47 and 49 controlsthe magnitude and direction of the magnetic flux traversing the ends ofthe core portions to thereby provide a finer control of convergence thanis easily achieved by adjusting the slide assembly 5 alone. 7

The U shaped core is positioned on the slide assembly 5 between thevarious outwardly extending positioning tabs 37, the core portions 47and 49 with the magnet 51 therebetween being retained bet-wen thepositioning tabs 1 37 by the action of the integral spring fingers 39 inexerting opposing forces thereon. With the U shaped core 35 assembled tothe slide assembly 5 in this manner, the top portions of certain of thepositioning tabs 37 may be deformed by heat to lock the U shaped core 35in place. As an alternative cement or wax might be employed to lock theUshaped core 35 to the slide assembly 5 and to maintain the magnet 51 inthe desired angular position with respect to the core portions 47 and 49after convergence is achieved.

Referring to FIGURE 2, there is shown a front view of the assembly ofFIGURE 1 with both slide assemblies 5 in place and the entireconvergence assembly positioned on the neck 54 of a cathode ray tubehaving a plurality of linearly arrayed electron beams 55 passingtherethrough. For purposes of simplicity, the pole pieces internal tothe tube neck 54 have been omitted; however, it will be appreciated thatsuch internal pole. pieces would normally'be employed to complete thevarious magnetic circuits and achieve the necessary convergence.

tions 7 and 8 are overlapped so that the distance across The convergenceassembly of the invention is retained on the, tube neck by aninterference fit between the portions 7 and 8 of the generallycylindrical member 1. In order to achieve the interference fit the radiiof the portions 7 and 8 are chosen to be equal to the maximum radius tobe encountered within the tolerances of the tube neck. However, thecenters of the radii defining pordiameter to be encountered within thetolerances of the tube neck. Thus, the intermediate integral spring loopportions 9 bias the portions 7 and 8 toward each other so that aninterference fit exists between these portions and the tube neck 54. Itwill be appreciated that, due to the presence of the spring loopportions 9, the assembly of the invention is easily assembled to theneck of the tube by sliding the assembly along the neck to the desiredposition, the aforementioned interference fit subsequently maintainingthe assembly in the desired position.

The slide assemblies 5 are shown assembled to the deck portion 14 by thescrew 43 passing through the slots 41 and being received by the holes 28in bosses 27. In this manner, the position of the U shaped core 35 withrespect to the electron beams 55 can be changed by loosening the screws43 and slid-ing the slide assembly 5 in the desired direction, the endsof the U shaped core 35 being received by the apertures 11 in thecylindrical member 1 at the extreme of the travel of slide 5 to allowthe U shaped cores 35 to be brought into close proximity to the variouselectron beams. Similarly, the angular position of the magnets 51 withrespect to the core members 47 and 49 can be varied to control the fluxto thereby allow fine adjustment to achieve the necessary horizontalconvergence.

Additionally, windings 5 7 are positioned on the arms of the U shapedcore 35 to provide for horizontal size correction. Suitable connections(not shown) are made between the windings 57 and the appropriateterminals 25.

Referring to FIGURE 3 there is shown a rear view of the convergenceassembly of FIGURE 1 showing the positioning of a pair of verticalconvergence controlling E *shaped core members 58 at opposite sidesofthe gen} manner to the magnet 51. A winding 65 is positioned on eachcentral arm 61 to provide for vertical size correction, connections (notshown) being utilized to connect 'each winding 65 to the appropriateterminals 25.

An integral receptacle generally shown at 66 is pro vided on the deckportion 14 for each E shaped core member 58. Each receptacle 66comprises "an end wall portion 67 and a pair of side wall portions 69.In addition, outwardly extending locating tabs 71 are provided foraccurately positioning the E shaped core members. The integral springfingers 21 serve to bias the U shaped member 59 against the central arm61 with the ferrite magnet 6-3 interposed therebetween and to maintainthe E shaped core member in the desired position. The ends of the Eshaped core in this position are interposed in the spaces betweenadjacent one-s of the longitudinally extending fingers 13 so thatproximity between the E shaped core and the various electron beams isassured;

In addition, as with the U shaped core members 35, certain of theelements of the receptacle 66' can be deformed to rigidly fix the Eshaped core in the desired position or cement or wax might be employedfor this purpose. Again,.as with the ferrite magnets 51, the ferritemagnets 63 can be rotated to control the magnitude of the flux :and thusthe convergence of the various beams. It is found that the provision ofthe magnet 63 in this manner is suflicient to effect verticalconvergence in nearly all situations so. that a slide is not necessaryas is the case for horizontal convergence. However, in

. some applications it might 'be necessary to employ a slide for the Eshaped core members 58 similar to slide assembly 5.

Referring to FIGURE 4, there is shown a top view of the convergenceassembly of the invention as positioned on the neck 54 of the cathoderay tube. As shown, a circular clamp 73 is utilized to encircle thelongitudinally extending fingers 13 to rigidly afiix the assembly to thetube neck.

Although the invention has been described with respect to certainspecific embodiments, it will be appreciated that modifications andchanges may be made by those skilled in the art Without departing fromthe true spirit and scope of the invention. In particular, although thedepicted embodiment of the invention has been directed toward use with acathode ray tube employing in-line guns, it will be appreciated that thedepicted device might be easily modified for use with the moreconventional triad gun tube.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

1. An electron beam convengence apparatus for use with a cathode raytube including a neck traversed by a plurality of electron beams, saidapparatus comprising;

(a) a generally cylindrical member adapted to encircle the neck of thecathode ray tube in engagement there with,

(b) a generally fiat body member integral with said generallycylindrical member and extending generally transverse thereto,

, (c) a plurality of magnetic core members mounted to opposite surfacesof said body member and arranged about said cylindrical member in spacedrelationship one with the other to control the convergence of theelectron beams.

2. The convergence apparatus defined in claim 1 wherein said generallycylindrical member includes an integral spring loop portion for biasingsaid generally cylindrical member against the neck of the cathode raytube.

3. The convergence apparatus defined in claim 1 wherein said generallycylindrical member includes first and second semicylindrical portionshaving first and second integral spring loop portions therebetween.

4. The convergence apparatus defined in claim 3 wherein the radius ofeach of said semi-cylindrical portions is substantially equal to themaximum radius of the tube neck Within the tolerances thereof and thecenters of the radii of each semi-cylindrical portion are overlapped sothat the distance betwen said semi-cylindrical portions through saidcenters is less than the minimum diameter of the tube neck within thetolerances thereof.

5. The convergence apparatus defined in claim 1 wherein said generallycylindrical member is provided with a plurality of axially extendingfingers adapted to be clamped to the tube neck to rigidly mount saidconvergence apparatus thereto,

6. An electron beam convergence apparatus for use with a cathode raytube including a neck traversed by a plurality of linearly arrayedelectron beams, said apparatus comprising;

(a) a generally cylindrical member adapted to encircle the neck of thecathode ray tube in engagement therewith,

(b) a generally fiat body member integral with said generallycylindrical member and extending gener-ally transverse thereto,

(c) first and second generally E shaped magnetic cores,

each comprising first and second core elements having a permanent magnetinterposed therebetween.

(d) said first and second generally E shaped magnetic cores, beingdisposed in diametrically opposed relationship with respect to saidgenerally cylindrical member and being mounted to a first surface ofsaid body member, and

(e) first and second generally U shaped magnetic cores, each comprisingfirst and second core elements having a permanent magnet interposedtherebetween,

(f) said first and second generally U shaped magnetic cores beingdisposed in diametrically opposed relationship with respect to saidgenerally cylindrical member and being slideably mounted to the surfaceof said body member opposite said first surface.

7. The convergence apparatus defined in claim 6 wherein said body memberincludes first and second slide assemblies having said first and secondU shaped cores respectively positioned thereon and said body memberfurther includes channel members adapted to slideably receive said slideassemblies.

8. The convengence apparatus defined in claim 7 wherein each of saidslide assemblies includes a plurality of integral spring fingersengaging said channel members to bias the slide assembly against saidbody member.

9. The convergence apparatus defined in claim 7 wherein each of saidslide assemblies includes a plurality of integral spring members enaging the first and second core elements of the associated U shaped coreto exert retaining forces thereon.

10. The convergence apparatus defined in claim 6 wherein said firstsurface of said body member is provided With a plurality of integralspring members engaging the first and second core elements of theassociated E shaped cores to exert retaining forces thereon.

No references cited.

JAMES W. LAWRENCE, Primary Examiner. R. SEGAL, Assistant Examiner,

1. AN ELECTRON BEAM CONVERGENCE APPARATUS FOR USE WITH A CATHODE RAYTUBE INCLUDING A NECK TRAVERSED BY A PLURALITY OF ELECTRON BEAMS, SAIDAPPARATUS COMPRISING; (A) A GENERALLY CYLINDRICAL MEMBER ADAPTED TOENCIRCLE THE NECK OF THE CATHODE RAY TUBE IN ENGAGEMENT THEREWITH, (B) AGENERALLY FLAT BODY MEMBER INTEGRAL WITH SAID GENERALLY CYLINDRICALMEMBER AND EXTENDING GENERALLY TRANSVERSE THERETO, (C) A PLURALITY OFMAGNETIC CORE MEMBERS MOUNTED TO OPPOSITE SURFACES OF SAID BODY MEMBERAND ARRANGED ABOUT SAID CYLINDRIAL MEMBER IN SPACED RELATIONSHIP ONEWITH THE OTHER TO CONTROL THE CONVERGENCE OF THE ELECTRON BEAMS.